In a report made public in May, the researchers found that the number of prescription drug users had risen from two decades ago, when about 4 in 10 Americans had at least one prescription.

Several factors contributed to the rise, the report said. New and better drugs are constantly hitting the market, more people have health insurance that covers prescriptions, and drugmakers are spending more on marketing. Most of the marketing focuses on doctors, but the report noted drug companies' collectively spent $4.2 billion on direct-to-consumer advertising in 2005 - more than triple what they spent a decade before.

Cardiovascular drugs that control blood pressure and treat heart and kidney disease were the most common prescriptions for adults, followed by cholesterol-lowering drugs and anti-acid-reflux treatments. For children, remedies for asthma and allergies edged out antibiotics on the most-prescribed list. Antibiotics were, by far, the most common prescription for children from 1988 to 1994, but physicians have scaled back in recent efforts to prevent bacteria from becoming drug-resistant.

Here are the pill-popping percentages:

47.5%

The percentage of Americans who reported taking a least one prescription drug in the month before being surveyed, according to the CDC report. That's up from 39.1 percent from 1988 to 1994.

10.6%

The percentage of Americans who said they took five or more prescriptions in the month before being surveyed. Adults older than 65 were the most likely to fall into this category, and children were the least likely.

39%

The percentage of doctors in 2009-10 who were less likely to prescribe antibiotics for cold symptoms than they were in 1995-96. Unnecessary use of the drugs has caused many bacteria strains to become resistant.

70.2%

The percentage of Americans 65 and older who reported taking a cardiovascular drug to treat high blood pressure, heart disease or kidney disease, making these the most commonly prescribed drugs for the age group. These medications also topped the list for patients ages 18 to 64, with almost 18 percent taking them.

4 times

American adults' use of antidepressants increased more than fourfold between 1988 to 1994 and 2007 to 2010. Use rose in all age groups and both genders but was most common among middle-aged women.